The performance of a catalytic converter in an automobile will degrade as a function of time which in turn affects the catalyst's effectiveness for preventing the emission of harmful gases. Therefore, it is important to measure the degradation of a catalyst's performance as it ages. Early failure of a catalyst leads to undesirable emission levels-released into the atmosphere. To gauge the aging performance, it has been the practice to field test catalysts by road testing an automobile having the catalyst installed. However, this method of testing is both costly and time consuming. In order to avoid the necessity of road testing, attempts have been made to alter the operation of the engine and artificially accelerate the aging process.
The purpose of modifying the engine operating conditions is to assure that, after exposure to the accelerated aging, the catalyst reacts to emission gases in a similar manner as the catalysts which have been actually aged on a vehicle.
U.S. Pat. No. 4,878,380 teaches altering the operation of an engine by the introduction of gases into the intake manifold of the engine for the purpose of testing the engine catalyst. This technique has been used only to handle testing. Thus, the effect on the engine control module is important. Although this technique may be sufficient for testing, it will not allow for proper aging to occur because of the ability of the engine control module to correct the air fuel ratios.
To accelerate the aging process, engines have been used as programmable gas generators. These engines have been programmed to generate various gas mixtures and other additives have been added to the exhaust to further age the catalyst. However, to control an engine when so used is difficult. Control has been established by removing or blocking the engine control module so that it cannot compensate for engine abnormalities. However, if the engine control module remains connected and cannot compensate, it becomes disabled or dysfunctional and will not perform the other function needed to maintain a stable operating condition.
One potential solution would be to remove the engine control module; however, without the module, it would make the operation of the engine difficult. Also, if the engine control module were to be removed, important information which it contains would be lost. This information can be used to help maintain better control of the engine while operating under conditions which will accelerate the aging of a catalyst.
Thus, there is a need to develop a method for aging catalyst that uses a standard engine without the need to remove or alter the engine control module.